Technical Field
The invention relates to a circuit board structure and a manufacturing method thereof, more particularly, relates a circuit board structure having a cavity and a manufacturing method thereof.
Background
Generally, in order to manufacture a circuit board structure having a cavity, a copper alignment layer usually needs being formed on the core layer of the inner circuit structure for the following purpose. When laser ablates the circuit structure to form the cavity in the subsequent process, other than being considered as a laser blocking layer to prevent the circuit structure from being excessively ablated, the copper alignment layer may also be considered as a laser alignment pattern that is helpful in performing the laser ablation process. However, because the copper alignment layer is directly formed on the core layer of the inner circuit structure, the circuit layout of the core layer is restricted and the wiring flexibility of the core layer is reduced.